Swimming Pools

[Conor]

ICF is now becoming a standard way to build a pools. Insulation and structure in one.

[SteamyTea]

4 hours ago, Conor said:

ICF is now becoming a standard way to build a pools. Insulation and structure in one.

That does seem to be the way small ones are made now.

Block and liner was all the rage in the late 80's.

They were cheap to install and cheap to remove.

Depending on size, you can get GRP moulded ones.  They can be tricky to install correctly.

Insulation, which was not considered much when I was dealing with them, is now considered much more important.

 

All domestic pools end up cloudy.  Thankfully the chemical dosing is pretty easy these days, unlike a spa bath.

 

Is your pool indoors?  If it is, then make sure that anything holding your house together is rust proof.  Don't rely on the AC/Heat Recovery to stop the chlorine rusting everything.

[Onoff]

My mate built a kiddie pool much as you're suggesting using blocks and a liner. The liner he had made to fit and it is a perfect fit to the dimensions he gave the company. No wrinkles etc once filled. 

[AliG]

The pool continues to work fantastically well and is a big hit in the recent hot weather and with various guests we have.

 

The automated systems looking after the water continue to tick along with minimum maintenance.

 

I reckon you are talking about £500 a year for a couple of maintenance visits and to top up the chemicals.

 

Heating seems to be running to about £500 a year. I noticed that the two pipes supplying the pool heater are not insulated for the last 5m of their run so will insulate them this week and hopefully that will save a little bit. Last week was the lowest gas consumption I have seen since we moved in at around £2.50 a day which includes the cost of hot water.

 

The surprise cost is electricity. It is hard to separate the cost of the dehumidifier and pump from our other electricity consumption, but I reckon we are talking around £1000 a year.

 

The pool is set up for the filter pump to run 16 hours a day, I believe that we could cut the electricity cost by reducing this, but the water is beautifully clear and clean so I don't want to mess with it.

 

So around £2000 a year in costs which I think is a lot less than you might expect.

 

The humidity of the room is set at 60% which is actually lower than humidity levels outside in the recent weather. The pool has 0.55ppm of chlorine so I am not worried about corrosion issues, you wouldn't know there was a pool in the house. In the winter it is the warmest room in the house, but bizarrely the temperature is more steady so in the summer it has been cooler than other rooms.

 

 

 

 

[SteamyTea]

30 minutes ago, AliG said:

The pool has 0.55ppm of chlorine so I am not worried about corrosion issues,

Sooner or later you will be.

[AliG]

Tap water has as much or more chlorine in it, so I don't think it is an issue. Public pools have vastly more chlorine in them.

 

Clearly I will keep an eye on it. The room is well sealed and all the steel in the house is galvanised and painted.

[PeterW]

Worth switching to one of the alternative chemicals ..?

[AliG]

There are a lot of differences between a home pool and public pool.

 

This article explains the issues regarding steel corrosion.

 

https://atguv.com/2015/12/18/how-uv-can-reduce-corrosion-in-swimming-pool-structure/

 

Public pools are open all day and heavily used. They will probably have a higher level of chlorine in the 1-1.5ppm range. The swimming pool smell that we are used to is not chlorine but chloramines caused by reactions of contaminants with the chlorine. It is these which particularly attack stainless steel.

 

My pool has a UV treatment which breaks these down and you never smell that "swimming pool" smell.

 

On top of this the pool is rarely open for more than a few hours a week and rarely has more than 2 or 3 people in it, so you just aren't sending as many chemicals into the atmosphere. Public pools are normally set to a 30C room temperature and left permanently open and evaporating. You often see condensing water all over the place in these pools. You should not see that in a well insulated private pool. Mine is only wet where people splash water.

 

The combination of excessive temperature and humidity and chemicals in the atmosphere all lead to public pools frankly often being really unpleasant to be in and basically falling apart as everything is damaged by heat and humidity and chemicals. You really should not be getting a similar situation in a private pool.

 

Edited August 4, 2019 by AliG

[Onoff]

I recall seeing one of the Center Parcs sub tropical swimming paradise. The effect was somewhat ruined by all the rust streaks down the structural steel holding the dome up! Thereafter we went back and it was all netted / scaffolded out which again didn't look great. Our local leisure centre, ALL the bolts holding the flume sections together looked rotten last time I was there.

 

[Jeremy Harris]

As an illustration of just how corrosive chlorine can be, I have a 5kg tub of hypochlorite ("pool shock") that I used to disinfect our borehole after it was drilled and cleaned out.  I sealed up the container and left it in the cupboard under the utility room sink.  Despite being sealed, enough chlorine has escaped to corrode the pipes etc under the sink, and seriously rust all the sink fixings. 

[AliG]

The pool has clearly been very popular in the lockdown period.

 

In response to another thread re pools, dehumidifiers, corrosion etc I thought I would have a look around.

 

Chlorine - As previously pointed out, the pool sits between 0.5 and 0.55 ppm chlorine, this is the same level as tap water. This compares to around 3 in a public pool, so 6x as much. There is no actual chlorine directly involved. When the pool was installed they dosed it with some salt, considerably less than in sea water, and there is a tube in the plant room which uses hydrolysis to create chlorine from the salt when needed. The water tastes neither salty nor is there any chlorine smell.

 

Humidity - The room sits at a constant humidity level of 60% whether the pool is open or closed. When the pool is closed the room temperature is 22-23C and the water temperature is  29C. When you open the pool, the dehumidifier kicks in and heats up the air to 25-26C. As the pool is normally closed and the room is not overly warm humidity is not an issue and the room is quite pleasant to sit in. At the same level of humidity, 30C air holds almost twice as much water as 20C air. thus the air holds considerably less water than the air on a Florida summer day. The only time I ever see any hint of condensation in the room is in the winter, the door lock on the french doors is cold and water condenses on it. There is never any condensation on the window frames or windows. Rationel would not warrant them for use in a pool and recommended uPVC but knowing that humidity would be well controlled we ignored this.

 

So my conclusion on corrosion risk is that it is minimal as long as you control humidity well, do not use chlorine and do not have the pool open all the time. However, to do this adds considerably to the capital cost of the pool. The pool cover and air handling equipment cost as much as the pool itself.

 

Relative to the 5kg of sodium hypochlorite, it looks like it would only take 60g of hypochlorite to get my pool to 0.5ppm of chlorine.

 

I took a picture of the door furniture where presumably corrosion would start to show. It still looks as good as new after three years.

 

I think water damage is a much more pertinent issue than corrosion. The walls around the pool are tiled and we used special pool silicon to seal around the pool edges. The floor is tiled also, although as someone pointed out water does pool on the floor, because no one thought to give it a run back down towards the pool. Something we will do when it needs retiled. However, the builders did not seal the bottom on the door frame to the changing room (despite me asking) it only took a few weeks of use before it started to blow out and I got it sealed.

 

Running costs continue to be very low relative to the historic scary costs of running a pool. Indeed they have probably fallen as gas and electricity tariffs have fallen. I reckon that we are running at around £1600 a year for gas, electricity and servicing, my previous estimate of the electricity use was probably a little high now that I have figured out the use in other parts of the house.

 

One thing that I will be watching is the pool lights. We have 2x 36W LED lights in the pool. The original lights broke, one never worked properly. The installer said it was the fault of the builders for allowing the pool to sit full of dirty  water for ages before it could be commissioned. Eventually I agreed to pay for the lights if he installed them, that was £800. On discussion he said that he is finding that LED lights break after about 5 years as over time small amounts of water get onto them and break the drivers. He said that this was a problem versus the old 300W incandescent bulbs. For all the time the lights are on if this continues the 300W bulbs may actually be a lot cheaper to run.

 

[hallega]

WOW, that's really nice, thanks for the info, I may just look up the company when the time comes. Cheers, Lynn

[Onoff]

On 19/05/2020 at 20:13, AliG said:

 

 

Is that top magnetic catch not dead central to the door?

[AliG]

It is not, looking at a few of them, I think they have maybe set them back a bit so that the strike plate is not too near the edge of the frame.

[Onoff]

28 minutes ago, AliG said:

It is not, looking at a few of them, I think they have maybe set them back a bit so that the strike plate is not too near the edge of the frame.

 

At least you've got "proper" doors! ?

 

I had to get mine dead centre and dead square, these cheap doors are so thin. 

 

 

[Trw144]

@AliG Can I ask what size your pool

heating demand is in terms of boiler size and annual heating requirement - I'm planning a 5/6m x 10m pool and deciding how I heat the pool has a big effect elsewhere in the build design. The site doesn't have mains gas (and I haven't as yet looked to see how far away it is/would cost), so current thoughts are either biomass or a heat pump. 

[AliG]

My pool is 9x3.7 I think. And 1.3m deep. Should have made it 1.35m maybe.

 

It is just heated by the gas boiler and I reckon it costs about £500 a year, around 25000kWh.

 

With an ASHP you’d probably be looking at 7000kWh of electricity so almost £1000. I guess the low temperature will help to keep the COP higher.

 

The larger cost for me is actually the pump and dehumidifier. I think they use around £8-900 a year in electricity.

 

Servicing costs for me are around £500 a year.

 

The big cost really is the space. Pool room plus changing room and plant room are around 85sq metres so call it 150k of space. The pool and all the plant was about 80k and because it is set into the ground there is also extra groundwork and foundation cost. I had considerably bigger quotes for the pool itself and reckon I got a pretty good deal. Think it would be about 100k from the same guy today as it was quoted in 2015.

Edited January 20, 2021 by AliG

[Trw144]

Thanks. I have just submitted an application to see how much a mains gas connection would be as its the first choice, but as far as I can tell from the maps the mains is several hundred meters away so will see what kind of figure they come back with. So, roughly an average of 65 kW a day - presumably the gas boiler kicks in several times a day to keep the water to temperature constant 24/7? 

 

I have distributor pricing for solar thermal so an oversized system should allow for much of the summertime use to be covered, it's finding the solution for the  darker months that is my current quandary. The real life COP of heat pumps always scares me, although as you say the lower temps required by a pool should help with this.

 

 

[AliG]

Just a quick update.

 

Due to COVID the guy was not able to get out and service the pool, we would have had an emergency visit if anything was required.

 

The pool went over a year without being serviced and everything continued to work perfectly, meanwhile I just saw an installer online recommending that if you have one of their pools installed it should be serviced every two weeks (every week if the pool is outside)! Admittedly I do have to drop the cleaning robot in every two weeks and then pull it out when it is done, but that is it. If any of the chemicals run out, I can just swap them over in seconds.

 

So I think for the Dryden Aqua DA-GEN system that I have which automates pool disinfection then 6 monthly visits are fine which massively reduces running costs.

 

 

Edited July 17, 2021 by AliG

[Declan52]

1 hour ago, AliG said:

Just a quick update.

 

Due to COVID the guy was not able to get out and service the pool, we would have had an emergency visit if anything was required.

 

The pool went over a year without being serviced and everything continued to work perfectly, meanwhile I just saw an installer online recommending that if you have one of their pools installed it should be serviced every two weeks (every week if the pool is outside)! Admittedly I do have to drop the cleaning robot in every two weeks and then pull it out when it is done, but that is it. If any of the chemicals run out, I can just swap them over in seconds.

 

So I think for the Dryden Aqua DA-GEN system that I have which automates pool disinfection then 6 monthly visits are fine which massively reduces running costs.

 

 

Every two weeks!!! Some company is making a fortune with that schedule.

[SteamyTea]

2 hours ago, AliG said:

 

The pool went over a year without being serviced and everything continued to work perfectly, meanwhile I just saw an installer online recommending that if you have one of their pools installed it should be serviced every two weeks (every week if the pool is outside)

Do you mean (or the installer mean) service, or routine maintenance?

[AliG]

Looks like a lot of the stuff my pool does automatically. Guess you might call it routine maintenance.

 

TBF the guy who put mine in says a lot of owners have staff who look after them as part of looking after their house or garden.

 

https://deependpools.co.uk/pages/service

[Ferdinand]

5 hours ago, AliG said:

Looks like a lot of the stuff my pool does automatically. Guess you might call it routine maintenance.

 

TBF the guy who put mine in says a lot of owners have staff who look after them as part of looking after their house or garden.

 

https://deependpools.co.uk/pages/service

 

Staff !

 

Love it.

 

Self-build Wentworth Woodhouse coming along real soon now !

 

[AliG]

4 hours ago, Ferdinand said:

Staff !

Yeah. He was talking about someone putting in an outdoor pool.

 

I said they are crazy as they cost a fortune to heat and would need constant cleaning.

 

He said it’s ok the staff just do it.

[Nickfromwales]

7 hours ago, AliG said:

Yeah. He was talking about someone putting in an outdoor pool.

 

I said they are crazy as they cost a fortune to heat and would need constant cleaning.

 

He said it’s ok the staff just do it.

I put two gas boilers in for an outside pool ( uncovered!!! ) and the guy said he would just “live with the £5-6k gas bill p/a………..”

That was about 6/7 years ago.  

I strongly advised 15kW of ST on the roof ( 2x 7.5kW system split E&W ) but he said he would think about it but wasn’t overly bothered. Said gas was just a button push so a simple solution. Wtf. 

Edited July 18, 2021 by Nickfromwales